There are various proposals for construction of tires which are non-pneumatic so as to avoid the problem of puncturing and which provide acceptable cushioning and performance characteristics.
Where the proposals are concerned with solid tires constructed predominantly from elastomeric material, a difficulty arises in dissipating heat generated in the tires, and resultant accumulation of heat may lead to degradation of the tire material.
Other proposals overcome or avoid the problem of heat accumulation by providing cavities in the body of the tire. The cavities not only reduce the overall mass of the tire so as to reduce the extent of heat generated but also enhance heat dissipation. In certain proposals, the cavities are so arranged as to result in the formation of a load carrying and supporting structure within the tire between its inner and outer peripheries. Such a structure within the tire is arranged to have load bearing capabilities while also being capable of deformation to provide cushioning. Several such proposals are disclosed in European Patent Application Nos. 0159880 and 0245789 and each comprises a structure in the form of circumferentially spaced apart ribs interconnected by a central web which is generally planar and extends circumferentially around the rotational axis of the tire. With this structure, each section of the central web between neibouring ribs has a longitudinal extent aligned with the direction of rotation of the tire and consequently may be vulnerable to collapsing when the tire is subjected to lateral forces, particularly during cornering.